<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>原点发散</title>
    <style>

        @keyframes pluse {
            0%{

            }

            70%{
                width: 40px;
                height: 40px;
                opacity: 1;
            }

            100%{
                width: 70px;
                height: 70px;
                opacity: 0;
            }
        }

        .city{
            position: relative;
            margin-left: 100px;
            margin-top: 100px;
            width: 200px;
            height: 200px;
            background-color: black;
        }
        .point{
            transform: translate(-50%,-50%);
            position: absolute;
            top: 50%;
            left: 50%;
            width: 10px;
            height: 10px;
            background-color: skyblue;
            border-radius: 50%;
        }


        .city div[class^=plase]{
            transform: translate(-50%,-50%);
            border-radius: 50%;
            position: absolute;
            top: 50%;
            left: 50%;
            width: 10px;
            height: 10px;
            float: left;
            box-shadow: 0 0 12px green;
            animation: pluse 1.2s linear;
            animation-iteration-count: infinite;
        }

        .city div.plase2{
            animation-delay: 0.4s;
        }

        .city div.plase3{
            animation-delay: 0.8s;
        }

    </style>
</head>
<body>
<div class="city">
    <div class="point"></div>
    <div class="plase1"></div>
    <div class="plase2"></div>
    <div class="plase3"></div>
</div>
</body>
</html>